There are plenty of cool slider plugins available for WordPress. Not all of them allow you to easily share before/after images with your audience though. Ultimate Before After Slider is just the plugin for the job. It has a fully responsive design that lets you showcase before-after images like top viral websites. The plugin has a horizontal and vertical mode.
Ultimate Before After Slider supports hover and drag interaction. It has 3 ribbon and label display modes. If you are using images from other sources, you can always add image credits under your slider. The plugin supports an unlimited number of sliders on each page. To use it, simply create a slider, click on the shortcode and upload images.
The Ultimate Before After Slider plugin is ready for mobile devices. It supports custom colors and label text. This is a commercial script.